The present invention is directed to a device designed to provide an easy to use, inexpensive clinical tool for measuring two-point discrimination. The invention is capable of evaluating sensory cutaneous nerve function by providing a single hand-held device in which a practitioner can vary gaps between metal prongs which, when pressed against the body surface of a subject, measures the sensory nerve function of that subject by evaluating the subject""s perceived recognition of the pressure applied.
There are currently available devices designed to provide a practitioner with the means to measure two-point discrimination for evaluation of sensory cutaneous nerve function and sensory re-education. Such products include one or more molded plastic discs generally octagonally shaped with each side having imbedded therein metal prongs, having hemispherical tips, and all of the same diameter. These discs can be made available in pairs with each disc having a face supporting a single metal prong and other faces supporting metal prongs in pairs where the spacing between metal prongs of each pair varies. Such devices are designed to test sensory nerve function of a patient who is suspected of having, or has had, sensory nerve damage. Such sensory dysfunction is known to occur due to a variety of causes such as trauma affecting the continuity of nerve fibers, disease processes including leprosy, diabetes, multiple sclerosis and other diseases resulting in diminished nerve conductivity and nerve compression syndromes. The data gained from evaluation with such instruments provides an indication of the degree to which nerve damage has progressed and/or the degree to which recovery has occurred. The data thus obtained can be used to determine appropriate medical and/or surgical treatments to alleviate nerve compression or causes of interference. Data can be utilized in assessing the success of therapies and therapeutic modalities directed towards aiding in the restoration of nerve function or adaptation to nerve dysfunction. The readings provide an indication of the degree of damage to the patient""s sensory nerves and/or a measure of recovery from damage to the patient""s sensory nerves.
The two-point discriminator is a tool in the arsenal of the practitioner for determining sensory perception. The practitioner is able to measure sensory nerve damage, for example, by determining when the patient is able to discriminate between two distinct points of contact on the skin. When compared to data derived from normal, healthy subjects, such information can be used as an indication of the degree of a patient""s sensory nerve damage or as a measure of recovery from damage to the patient""s sensory skin nerves.
FIG. 1 depicts a typical prior art device in the form of a two-point discriminator. Specifically device 10 in the form of an octagon having eight flat faces 11 is sized to fit within the hand of a practitioner. Emanating from each face 11 are one or more metal prongs 12, 13, 14, etc. Face 11 supports a single metal prong 12 which itself can be placed against a patient""s skin to determine sensory nerve damage. When rotated within the practitioner""s hand, the patient""s skin can then be made to contact pairs of metal prongs of varying gaps. For example, for the device shown in FIG. 1, metal prongs 13, 14, etc. are shown with gaps of two to eight millimeters. In addition, as noted above, the patient can be made to contact a single metal prong 12 and metal prongs having spacings of as much as 25 millimeters can be made to contact the patient""s extremity by touching one""s skin with pairs 12 and 13. Additional discs can be provided in a set in order to increase possible spacing choices to increase the value of this two-point discriminator as an evaluation tool.
Although devices such as those shown in FIG. 1 represent valuable diagnostic tools, they are not without their drawbacks. As noted, two-point discriminators commonly used by practitioners require two or more instruments to cover a full range of pin gaps. While in use, practitioners may be required to switch between several ranges of gap settings several times. This is cumbersome and oftentimes not practical as various instruments can be lost or misplaced frustrating a practioner""s ability to conduct a seamless professional test. Furthermore, prior art devices such as those shown in FIG. 1 having metal pins have proven problematic as such pins tend to bend if accidentally dropped onto a hard surface resulting in a loss of accuracy.
It is thus an object of the present invention to provide a two-point discriminator whereby various gaps can be established in a repeatable, convenient fashion with a single device. This and further objects will be more readily apparent when considering the following disclosure and appended claims.
The present invention relates to a hand-held, two-point discriminator which provides variable settings designed to test for nerve sensory function. The device is configured in the form of a body portion comprised of a top disc of substantially circular geometry and a bottom disc of substantially circular geometry. The top disc and bottom disc are provided with substantially equal diameters and are concentric in circumference when joined about a common centrally located axis. The discs are rotatable with respect to each other about their axis and each is provided with a plurality of tip members ideally molded as a single unitary construction within the recited top and bottom discs. Distances between pairs of points can be adjusted by rotating the top and bottom discs with respect to one another about the central axis. As a preferred embodiment, tip spacing within pairs can be established in a repeatable fashion in order to determine if the patient can discriminate between points.